Refining the formation and early evolution of the Eastern North American Margin: New insights from multiscale magnetic anomaly analyses

Journal of Geophysical Research B: Solid Earth
By: , and 

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Abstract

To investigate the oceanic lithosphere formation and early seafloor spreading history of the North Atlantic Ocean, we examine multiscale magnetic anomaly data from the Jurassic/Early Cretaceous age Eastern North American Margin (ENAM) between 31 and 40°N. We integrate newly acquired sea surface magnetic anomaly and seismic reflection data with publicly available aeromagnetic and composite magnetic anomaly grids, satellite-derived gravity anomaly, and satellite-derived and shipboard bathymetry data. We evaluate these data sets to (1) refine magnetic anomaly correlations throughout the ENAM and assign updated ages and chron numbers to M0–M25 and eight pre-M25 anomalies; (2) identify five correlatable magnetic anomalies between the East Coast Magnetic Anomaly (ECMA) and Blake Spur Magnetic Anomaly (BSMA), which may document the earliest Atlantic seafloor spreading or synrift magmatism; (3) suggest preexisting margin structure and rifting segmentation may have influenced the seafloor spreading regimes in the Atlantic Jurassic Quiet Zone (JQZ); (4) suggest that, if the BSMA source is oceanic crust, the BSMA may be M series magnetic anomaly M42 (~168.5 Ma); (5) examine the along and across margin variation in seafloor spreading rates and spreading center orientations from the BSMA to M25, suggesting asymmetric crustal accretion accommodated the straightening of the ridge from the bend in the ECMA to the more linear M25; and (6) observe anomalously high-amplitude magnetic anomalies near the Hudson Fan, which may be related to a short-lived propagating rift segment that could have helped accommodate the crustal alignment during the early Atlantic opening.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Refining the formation and early evolution of the Eastern North American Margin: New insights from multiscale magnetic anomaly analyses
Series title Journal of Geophysical Research B: Solid Earth
DOI 10.1002/2017JB014308
Volume 122
Issue 11
Year Published 2017
Language English
Publisher AGU
Contributing office(s) Woods Hole Coastal and Marine Science Center
Description 25 p.
First page 8724
Last page 8748
Other Geospatial Eastern North American Margin